Number of banking offices.

No definition available.

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- Definition

Percentage of share in results of pooled business.

+ References

No definition available.

+ Details

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- Definition

Percentage of share in results of pooled business owned by third party.

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
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- Definition

Percentage of voting power owned by major shareholder.

+ References

No definition available.

+ Details

Name:	dgica_PercentageOfVotingPowerOwnedByMajorShareholder
Namespace Prefix:	dgica_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock ownership percentage held by major shareholder.

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock ownership percentage owned by third party.

+ References

No definition available.

+ Details

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Namespace Prefix:	dgica_
Data Type:	num:percentItemType
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- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

+ Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Organization - Additional Information (Detail)	9 Months Ended								9 Months Ended
Organization - Additional Information (Detail)	Sep. 30, 2013 Office Segment	Sep. 30, 2013 Subsidiaries [Member]	Sep. 30, 2013 Common Class A [Member]	Jul. 18, 2013 Common Class A [Member]	Dec. 31, 2012 Common Class A [Member]	Feb. 23, 2009 Common Class A [Member]	Apr. 18, 2013 Common Class A [Member] Minimum [Member]	Apr. 18, 2013 Common Class A [Member] Maximum [Member]	Sep. 30, 2013 Common Class A [Member] Subsidiaries [Member]	Sep. 30, 2012 Common Class A [Member] Subsidiaries [Member]	Sep. 30, 2013 Common Class B [Member]	Dec. 31, 2012 Common Class B [Member]
Business Acquisition [Line Items]
Outstanding stock percentage	48.20%
Number of banking offices	13
Stock ownership percentage owned by third party	51.80%
Number of operating segments	4
Stock ownership percentage held by major shareholder			38.00%								76.00%
Voting power percentage of outstanding common stock	66.00%
Percentage of share in results of pooled business		80.00%
Percentage of share in results of pooled business owned by third party	20.00%
Number of common stock shares purchased				500,000		300,000
Common stock shares purchased			275,932						4,240	92,364
Increase in number of shares			40,000,000		30,000,000		30,000,000	40,000,000			10,000,000	10,000,000